180 ANATOMICAL DESCRIPTIONS. [December. 



Mea^dhii^ A labi/rinthica. (PlateVIII.fig.il.) A 

 calcarious mass, deeply and irregularly furrowed, consti- 

 tutes the dwelling of this species. 



The animals are found at the bottom of the furrows; 

 mouth with six plaits on each side, encircled with red and 

 yellow, mingled with green; the tentacula are from eigh- 

 teen to twenty in number, long, red, with small white 

 spots; the membranaceous expansion, which covers the 

 furrows of each side, are brownish red. 



Inhabits the island of St. Thomas. 



AsTREA dichotonia, (Plate VIII. fig. 12,) A calca- 

 rious mass, divided in a dichotomous manner, thick, irre- 

 gular, bearing at its summit the last stratum of cdiulest 

 "which are small, hexagonal, irregular; animal reddish^ 

 furnished with twelve tentaculaj of a middling size, and 

 white; mouth small, oval; centre of the disc^ and the body^ 

 reddish; the animal, as in the foregoing, when expanded, 

 rises greatly beyond its cellule. 



Inhabits the island of Nevis. 



r 



AXJTOMiCAL nESClilPTIOJyV^ OF SEVERAL OF TOE FOUE- 

 GOIjYG AjMMALS. 



Actinia ultramarina. (Plate VII. fig. 4, 6.) A sec- 

 tion of this animal, cut vertically, Mdiilst it is contracted, 

 presents a half sphere, flattened at its extremities.^ Its 

 skin, though not thick, is strong and coriaceous, and 

 forms several cavities. If one takes the animal in its 

 swimming position, the first cavity is that which contains 

 the air-bladder disk; this cavity is smooth, without any 

 other appearance of an opening than the upper one, which 

 is capable of being dilated or contracted. I was not ena- 



